1. Field of the Invention
The present invention relates to methods of, and means for recording and recalling timing information and identifying information related to events.
2. Description of the Related Art
Event logging systems are used to record information over a period of time for retrospective analysis. Such systems comprise some form of memory into which data corresponding to input signals are stored along with information identifying the time of the event. When it is desired to analyze the logged data, the event identifying and timing information is recalled and processed.
An example of such a logging system is a game playing device which records player responses along with the time at which the response was made. Such a device might include three pushbuttons, labelled "A", "B", "C", a clock/calendar device and digital memory arranged so that when one of the buttons is pressed, data identifying which button was pushed as well as the current time/date are stored in memory. This allows the device to be used for playing a quiz game. As the responses to multiple-choice questions are stored along with the time the response was made, the information can subsequently be recalled from memory for score calculation. The timing information is required to ensure that the responses were made during the time window allowed for response, and also for correlating the responses with questions.
In prior art logging systems, timing information is provided by a clock/calendar system typically comprising a stable oscillator driving suitable counting/calculating means. So that the timing information recorded is accurate, the oscillator must be stable and set to the exact frequency required and the time/date must be correctly set before logging begins. Logged information can be incorrectly time-stamped if, for example, the frequency of the oscillator is incorrectly set or the wrong time or date has been set.